Greer,
Last summer I completed a 5 acre pond in an area with marginal soil, ie mostly clay but with some significant sand strata, I am not a pond expert by any means. Thankfully and I believe due to many precautions and good practices (including some my contractor argued against, like a vibratory roller), my pond is currently holding water as good as if it were lined with a synthetic liner. I am an industrial contractor with 30+ yrs of experience, including soils and geotechnical work, and I applied the practices I've learned to compacting and manipulating soil for my pond, ie making dirt hurt:-)
Here are a few items you may want to consider:
First you must have enough good clay soil on your site to manipulate over any suspect (sand, silt) areas. If your site is totally clay with good impermiablity, then you may not need to compact much if at all if its an excavated pond with no dam. If the pond is excavated and will not include a dam, its a straightforward effort. Any excavated areas not containing clay need to be cored and/or capped with good clay and 24" is a commonly recommended thickness for capping/coring.
Clay capping should be done in ~8" lifts (layers) and compacted with a vibratory pad foot roller ideally. An 8" lift of loose clay will compact to a ~6" compacted layer. Make sure the clay isnt too wet or it will "pump" and never compact.
If your pond is an embankment pond, the dam must be cored into good clay. A deeper core trench is generally better than a shallower core trench, but the most important thing is to tie in to good clay. From the bottom of the core trench, start spreading the 8" layers of good clay with the proper moisture content and compact each one with the roller. When properly compacted the roller "walks out", which means the pads do not sink down very deep at all into the compacted soil. A good rule of thumb is to at least roll over the lifts 5-6 times. If the clay will not compact after 10 rolls or so, it may be too moist. Do not place lifts over other lifts that are not properly compacted and/or contain too much moisture.
The entire dam is built using this process. I know this is overly general but hope it helps. Most would agree that a dozer will not produce adequate compaction. A scraper pan can compact better than a dozer if used correctly, but not as good as a vibratory roller.
Best of luck and let me know if you have any questions about the above.
Thanks for all the detailed info. Half of my pond will have a dam because the area we want is basically sloping downward and continues on. So we're going to catch it and hold it.
Unfortunately, due to my experience working with contractors in the area on past projects, I can say for certain that I'm not going to find anyone with attention to detail and knowledge that you have.
All the contractors say they don't do compaction. Probably they don't have the equipment and if they did wouldn't know how to use it.
Since I have good soil (everyone in the area has told me that), could I maybe hire one of these dozer guys to dig the pond and put in the dam and then hire someone else to come do the compaction?
